11.8.1 Tear deficiency, ocular lubricants, and astringents
The severity of the condition and patient preference will guide the choice of preparation.
These preparations are available under the Minor Ailment Service (MAS)/can be purchased from community pharmacies.
Hypromellose 0.3% (also available as 0.5%) is the recommended preparation for the treatment of reduced tear secretion but it needs to be instilled frequently for adequate relief.
Carbomer 980, 0.2% (eye drops, single dose units) has a longer duration of action than hypromellose and is easier to administer. Applied 3-4 times daily or as required.
Polyvinyl alcohol (eye drops proprietary name Liquifilm Tears®) which contains either polyvinyl alcohol 1.4% or polyvinyl alcohol 1.4% plus povidone 0.6%) is used to increase the persistence of the tear film when surface mucin is reduced.
Simple eye ointment (contains paraffin) is used as an ocular lubricant, applied at night.
Eye ointments containing paraffin are best applied before sleep, may cause temporary blurred vision, and should not be used during contact lens wear.
Acetylcysteine 5% and hypromellose 0.35% (eye drops, proprietary name Ilube®) is recommended as a mucolytic agent.
Minims® Artificial Tears (eye drops) contains hyroxyethylcellulose 0.44%, sodium chloride 0.35% with no preservatives. It may be used in patients who are allergic to the preservative used in the other preparations.
Sodium hyaluronate 0.4% (0.5ml single dose units Clinitas®) is available for restricted use for short-term use in patients with non-healing epithelial corneal ulceration/defects and patients with severe dry eye syndrome.
Sodium chloride 0.9% drops are short-acting but sometimes useful in tear deficiency. They can be used as 'comfort drops' by contact lens wearers, and to facilitate lens removal. Special presentations of sodium chloride 0.9% and other irrigation solutions are used routinely for intra-ocular surgery.
Systane® (eye drops and single-use eye drops) may be helpful following failure of therapy with first-line agents.
Tears Naturale® (eye drops) contains dextran '70' 0.1%, and hypromellose 0.3%. It may be helpful in patients whose symptoms do not improve with hypromellose drops.